Fiberglass is an important inorganic nonmetal reinforced material, and it will form glass fiber reinforced composites with excellent performance by compositing with various resins, which will be widely used in civil construction, communication and transportation, electronics, machinery, chemistry, etc. At present, there have been thousands of varieties and specifications of fiberglass with more than 50 thousand of applications. Among various fiber reinforced products, the glass fiber reinforced composites have accounted more than 85% of the total output.
E fiber was firstly produced by Owens Corning Company in America. At present, America and Europe are still the main consumption regions of fiberglass in the world. Though the fiberglass industry starts later in China, it develops rapidly. In 2004, the annual output of fiberglass in China had exceeded that in America, ranking the first place of the world; in 2010, the annual output of fiberglass in China had reached more than 50% of the total fiberglass output in the world with three large-scale manufacturing enterprises emerged: Jushi Group Co., Ltd., Chongqing Polycomp International Corporation and Taishan Fiberglass Co., Ltd., whose outputs and scales have ranked Top 6 among world fiberglass industry. Now, China has become the world largest fiberglass manufacture and output base, and also one of the most important research, development and innovation bases of fiberglass in the world.
I. Disclosure of Products
At present, the boracic medium-alkali glass (C glass) is used in small amount for producing acid-proof products of C fiberglass at aboard. Though the traditional E-glass (such as direct roving 362K/352B for LFT produced by Jushi Group Co., Ltd.; SMC/BMC roving 956/957 produced by OCV Company) dominate the market, it has many defects on performance, component, cost and process, such as insufficiency of tensile strength and elastic modulus, relatively bad chemical resistance, and easily-caused environmental pollution by some components of the glass. In order to overcome these defects, enterprises in various countries added some new glass components to conduct a number of research and development in recent years. However, although enterprises at home and aboard have developed many new fiberglass products, their development orientation and technical achievements are of no industrial application value in many cases.
Fluorine free glass was developed under environmental stress in recent year, and due to the replacement of fluoride by other fluxing agent, the cost of F free glass is raised. But many F free E-glass technologies do not have industrial application value, and most of relevant technologies are not put into production.
In the 1980s, Owens Corning developed a classical anti-corrosive glass fiber (E-CR glass fiber), which is the earliest B and F free glass fiber that can be put into practice. E-CR glass fiber is composed of SiO2—Al2O3—CaO—MgO with 3˜5% of TiO2, whose liquidus temperature exceeds 1200° C. and forming temperature is up to 1340° C. Although E-CR glass fiber contains no B and F, excessive TiO2 made it too dark, which confined its applications; and such high liquidus temperature and forming temperature are severe challenge for nozzle plates and refractory. It can be hardly used in practices for too difficult production and too high cost.
Owens Corning Company is an oldest production enterprise of E fiberglass. It had developed a kind of B free and alkali free fiberglass in late 1990s: Advantex, whose electric property and strength property are similar to E fiberglass and the chemical resistance approximate to ECR glass. For it does not contain boron, the volatilization of boron compounds during glass melting is avoid, so as to reduce the environmental pollution and the corrosion to fireproofing materials. However, the glass still contains fluorine, and the forming temperature, liquidus temperature and forming range ΔT required by component allocation for producing the glass need to change general equipment; the fiberglass adopts universal special device and its production cost is relatively high, which brings difficulties to large-scale industrial promotion.
II. Disclosure of Documents
Technically, fiberglass is a kind of fibrous material drawn after melting of various natural mineral materials into glassy state under high temperature in certain component ratio, which is, in essence, a kind of glass or a kind of fibrous glass, so it can be called as glass fiber or fiber glass. According to the component of glass, the fiberglass can be divided, in general, into alkali free fiberglass, medium-alkali fiberglass and high-alkali fiberglass, and the alkali free fiberglass is named as E fiberglass at aboard, whose content of alkalis oxide (Na2O, K2O and Li2O) is generally less than 1%.
At present, 90% of international fiberglass products belong to E-glass.
E-glass is generally called as E-glass in English. E-glass is also called as alkali free glass, a kind of borosilicate glass. It is now a most widely used glass component for fiberglass; for it has good electrical insulation and mechanical performance, it is widely used for producing electrical insulation fiberglass and producing special fiberglass for glass reinforced plastic in large amount (reference: Wang C Y, Chen M, Chen J H; Glass Manufacturing Process; Chemical Industry Press; published on Jul. 1, 2006; Page 182; Zhang Y M; Glass Fiber and Mineral Wool; Chemical Industry Press; revised on Nov. 1, 2010; Page 216).
Since its emergence at 1930s, E fiberglass has been continuously improved and has become a kind of important inorganic non-metal reinforced material. Now fiberglass is an independent industry system for reinforced polyester resin, epoxy resin, vinyl resin, phenolic resin, etc. which are widely used in architecture, transportation, military, and living. Among them, E glass is a product mostly used.
Because the fiberglass (hereinafter referred to as fiberglass) is a kind of glass in essence, it does not contain crystals; it is a network structure mainly constructed by Si and Al atoms with positive ion filled in interspaces. All traditional E-glasses contain B (boron), which also participates in network structure in glass. After being added into glass, various oxides will finally exist in atom form, which is not related to the compound added.
The conventional E glass fiber belongs to SiO2—Al2O3—B2O3—CaO system, which is characterized by good insulation, heat resistance, anti corrosion, and mechanically high strength, moreover, it has lower fiberizing temperature and wide range of operating temperature. With good processing performance, it has been used up to present since its emergence at 1930s. The conventional E glass contains a certain amount of boron and fluorine, which have a good effect on reducing the glass melting temperature and the surface tension and viscosity of glass flow, thus minimizing the difficulty of glass fiber production. However, boron and fluorine have adverse effect on the glass fiber in its strength and anti corrosion. Furthermore, boron and fluorine are prone to volatile heavily, especially fluorine, over 50% of which is likely to volatile. This not only wastes raw materials, but also seriously pollutes the environment. For this purpose, both China and overseas countries have strict policies on the control of its emission, which require glass fiber producers to equip matching waste gas treatment plants, undoubtedly, increasing the production cost.
Therefore, the research and development of low B and F, or even B and F free glass fiber has always been a development trend of the international glass fiber industry. Although a number of researches and technical inventions have come out, there still exist some practical problems. That is because B and F in the conventional glass fiber play a role in melting assistance and the reduction of glass flow surface tension, which can better improve the forming of glass fiber. With remarkable decreased amount of B and F, or even without B and F, viscosity of glass flow will highly increase, and the operating temperature must be higher, which enhances the difficulty in the forming of glass fiber. Thus we must search another matter to act as B and F, although this is a rather hard way.
U.S. Pat. No. 5,789,329 is a B free glass fiber containing 59˜62% of SiO2, 20˜24% of CaO, 12˜15% of Al2O3, 1˜4% of MgO, 0˜0.5% of F2, 0.1˜2% of Na2O, 0˜0.9% of TiO2, 0˜0.5% of Fe2O3, 0˜2% of K2O, and 0˜0.5% of SO3. This glass fiber has no B2O3 but contains some F2, whose liquidus temperature is over 1169° C. whilst ΔT is below 80° C. Although this glass fiber allows absence of B and F, its liquidus temperature shall be up to 1206° C. while ΔT is down to 38° C., which is rather difficult to be produced due to crystallization.
Application WO99/12,858 has designed a low B and F reinforced glass fiber, in which SiO2 58˜62%, CaO>22%, Al2O 10˜16%, MgO>1.5%, CaO+MgO<28%, R2O<2%, TiO2<1.5%, Fe2O3<0.5%, F2<2%, B2O3<2%. The content of B2O3 has been largely reduced in this glass fiber, but F2, Li2O, or B2O3 still needs to be more than 0.5%, so it is not truly B and F free. Furthermore, this glass fiber contains a large amount of alkali metals, which decreases the corrosion resistance of products.
Application WO99/12,858 has designed another reinforced glass fiber, which contains 54.5˜58% of SiO2, 17˜25% of CaO, 12˜15.5% of Al2O3, 0˜5% of MgO, R2O<2%, TiO2<1%, Fe2O3<0.5%, F2<1%, and B2O3<3%. It requires B2O3 content to be more than 2% when SiO2 content is higher than 57%. This invention made contribution to the reduction of boron and fluorine in glass fiber, but absence of boron and fluorine has not been fully realized yet. And its low content of SiO2 is unfavorable to its strength, which will confine its applications.
U.S. Pat. No. 6,818,575 provides a low B and F glass fiber containing 52˜62% of SiO2, 16˜25% of CaO, 8˜16% of Al2O3, 1˜5% of MgO, 0˜1% of F2, 0˜2% of Na2O, 0˜2% of TiO2, 0.06˜0.8% of Fe2O3, 0˜2% of K2O, and 0˜5% of B2O3. The forming temperature of this glass fiber is low and the forming range is good. To achieve these forming advantages, the formula in the inventor's claims has high contents of Li2O (0.6%˜1.4%) and TiO2 (0.5%˜1.5%), and over 0.9% of alkali metals. High content of alkali metals will largely reduces the corrosion resistance of glass fiber, and the production cost will be higher due to expensive Li2O raw materials.
Application WO2005/093,227 has designed a low B and F E glass fiber, which contains 59˜63% of SiO2, 16˜23% of CaO, 10˜16% of Al2O3, 1˜3.2% of MgO, 0˜0.5% of F2, 0˜2% of R2O, 0˜1% of TiO2, 0˜0.5% of ZnO, 0˜1% of MnO, 0˜0.5% of Li2O, and 0.1˜1.8% of B2O3. This glass fiber contains a little B2O3 much lower than the conventional E glass fiber, and contains MnO, which darkens the glass fiber. The forming temperature of this glass fiber is rather high (over 1350° C.), so it is hard to produce.
Application WO2005/092,808 has designed a similar low B and F E glass fiber, which contains 58˜63% of SiO2, 16˜23% of CaO, 10˜16% of Al2O3, 0.5˜3.5% of MgO, 0˜0.5% of F2, 0˜2% of R2O, 1˜1.5% of TiO2, 0˜0.4% of ZnO, 0˜1% of MnO, 0˜0.4% of Li2O, and 0˜1.5% of B2O3. This glass fiber contains not only a little B and F, but also MnO and CoO, which will darkens the glass fiber and confines its applications. Furthermore, the forming temperature of this glass fiber is also high up to over 1350° C., so it is hard to produce.
China Patent No. 200710069773.5 has designed an alkali free glass fiber containing 58˜62% of SiO2, 20˜24% of CaO, 12˜14% of Al2O3, 2˜4% of MgO, 0.0˜60.6% of F2, 0.73˜2% of R2O, 2% of TiO2, and 0.5˜50.6% of Fe2O3. This invention contains no boron, but its alkali metals are high, which decreases its strength and corrosion resistance, and 2% of TiO2 content will have adverse effect on the color of the glass fiber.
China Patent No. 200810121473.1 involves a low B and F glass fiber containing 54˜62% of SiO2, 20˜28% of CaO, 12˜18% of Al2O3, 2˜6% of MgO, 0˜0.4% of F2, 0˜5% of B2O3, 0˜0.8% of R2O, 0.1˜1% of TiO2, and 0.1˜0.5% of Fe2O3. Although this invention described in the claims that its formula contains no B2O3 and F2, the forming temperature and liquidus temperature will be high without F and B, causing it difficult to produce.
China Patent No. 200910099335.2 involves a low B glass fiber containing 57˜61% of SiO2, 20˜25% of CaO, 12˜16% of Al2O3, 1˜3.5% of MgO, 0˜2% of SrO, 0˜1% of CeO2, 0˜0.5% of MnO2, 0˜1% of F2, 0˜2.5% of B2O3, 0˜0.8% of R2O, 0.1˜1.5% of TiO2, and 0.1˜0.6% of Fe2O3. This glass fiber remarkably reduces B2O3 content but retains F2. To improve the performance of this glass fiber, expensive CeO2, SrO and MnO2 were added into the formula, which increases the production cost.
From the above we can see that, no matter for the purpose of environmental protection and for cost consideration, reducing B2O3 and F2 contents is an objective that the glass fiber counterparts are endeavoring to achieve, however, the reduction of boron and fluorine in the production of glass fiber will cause increased forming temperature and liquidus and large fiberizing difficulty. For this purpose, most glass fiber inventions retain some B2O3 or F2 more or less, and their proportions may be higher as they are easy to volatile; some other inventions added expensive composites or greatly increased the operating temperature, but practical production is too difficult to realize.
Aiming at solving this contradiction in an effective way, this invention completely disuses B and F materials in the glass fiber formula while ensures proper forming temperature and good fiberizing performance, thus mass production can be realized. In addition, with better tensile strength and corrosion resistance, this glass fiber will more widely used in many fields.